<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>rectangle</title>
  <link rel="stylesheet" href="./layout.css">
</head>
<body>
  <form id="main">
    <label>宽度：</label>
    <input type="number" id="width" min="0" autofocus required step="0.01"><span></span>
    <br>
    <div id="width-validate"></div>
    <label>高度：</label>
    <input type="number" id="height" min="0" required step="0.01"><span></span>
    <br>
    <div id="height-validate"></div>
    <label></label>
    <input type="submit" id="calc" value="计算">
    <br>
    <label>周长：</label>
    <input type="text" id="perimeter" disabled>
    <br>
    <label>面积：</label>
    <input type="text" id="area" disabled>
    <br>
  </form>
  <script src="//apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
  <script src="./main.js"></script>
</body>
</html>
